1. Field of the Invention
The present invention relates to a control device of an internal combustion engine.
2. Description of the Related Art
In an internal combustion engine, in the past, the fuel used has mainly been fossil fuels. However, in this case, burning such fuels produces CO2, which causes global warming. On the other hand, burning ammonia does not produce CO2 at all. Thus, there is known an internal combustion engine made so as to use ammonia as fuel and not produce CO2 (for example, see Japanese Patent Publication (A) No. 5-332152).
However, ammonia is harder to burn compared with fossil fuels. Therefore, when using ammonia as fuel, some sort of measure is required for making the ammonia easier to burn. Thus, in the above-mentioned internal combustion engine, exhaust heat is utilized to reform the ammonia so as to produce reformed gas comprised of hydrogen and nitrogen, the hydrogen in the produced reformed gas is stored in a hydrogen storing alloy, and the hydrogen stored in the hydrogen storing alloy is fed together with the ammonia in a combustion chamber so as to enable easier combustion even when using ammonia as fuel.
In this regard, to make the ammonia burn well, it is preferable to cause the ammonia stored in a liquid state to vaporize in the vaporizer and feed the vaporized gaseous ammonia into the engine intake passage or combustion chamber. In this case, to stably feed the gaseous ammonia into the engine intake passage or into the combustion chamber, it is necessary to suitably control the action of vaporization of the liquid ammonia in the vaporizer. However, the above-mentioned Japanese Patent Publication (A) No. 5-332152 does not suggest anything regarding this.